Although the reproductive process of welsh onion is relatively simple, the technical requirements of field management are relatively high. In order to achieve high yield and high quality, the management measures are summarized as follows:
1. Early planting and early transplanting, and proper planting is the key. Many years of production experience have shown that early transplanting welsh onion has significantly improved yields compared to late transplanting onion. In addition, reasonable close planting is an important measure for high quality and high yield of welsh onion, generally with a plant spacing of 4-6 cm and a row spacing of 25-30 cm.
2. Weeding grass should be timely to prevent locusts from causing rot. The cultivator can promote the growth of welsh onion roots and increase the permeability of the soil. When scallions are planted at a time when the temperature is high and the rainfall is heavy, there are many kinds of weeds, so weeding must be done in time to prevent the grassland; in July and August, it is the concentration of the northern region. During the rainfall period, it is easy to cause scallions roots, yellow leaves, and dry tips. In addition to preventing waterlogging, it is also necessary to break the table and scatter early so that the roots of scallions can perform various normal activities.
3. The top-dressing fertilizer should be applied properly, and high yield and quality are guaranteed. Based on the fertility characteristics of local green onions and the local fertilization habits, generally 30 kg of “Tianji†phosphorus and potassium nitrate are applied per acre, and 30 kg of “Tianji†phosphorus nitrate is applied in 7-8 months, and then applied in the following month. 25 kg of Phosphorus Nitrate.
Preparation of Fenebute
1. Prepare the first intermediate
Benzaldehyde and ethyl acetoacetate into ethanol, stir at room temperature under the catalysis of organic alkali reaction with filter cake filtration after 45 ~ 50 h, after the completion of the filter with ethanol elution filter cake, dry cake solids, then ethanol filtrate concentrated to a quarter of the original volume, to cold, concentrate filtering alcohol washing, solid, merging two solid is the first intermediate; The mole ratio of benzaldehyde, ethyl acetoacetate and ethanol is 1:2.5 -3:12-15.
2. Prepare the second intermediate
The first intermediate is added to the mass concentration of 20% sodium hydroxide solution, and the reaction is stirred at 85-90°C for 2-5 hours. After filtration, the filter cake is used for filtration. After filtration, the filter cake is washed, the filtrate is combined and cooled, and the filtrate is cooled by stirring for 3h. Solid second intermediate; The mass ratio of the first intermediate to the sodium hydroxide solution is I: 1.8-2.0;
3. Prepare the third intermediate
The second intermediate was dissolved in pure acetic anhydride solution for reflux 3 ~ 5h. After the reflux, the acetic anhydride was concentrated and dissolved with toluene. After the dissolution, ammonia water was added, and the reaction took place at 60_65°C for 1 ~ 1.5 h. Filtrate, wash and dry the precipitated solid to get the solid third intermediate; The mass ratio of the second intermediate, pure acetic anhydride solution, toluene and ammonia water is 5:1-1.2:0.5-0.8:0.5-0.8;
4. Prepare Finebute
The third intermediate was dissolved in 25% sodium hydroxide solution and cooled to _5°C ~ 10°C. After cooling, sodium hypochlorite was added slowly within 15-20min for 1h reaction, followed by ice bath reaction of 0.5 ~ 1.5 h and water bath reaction of 0.5 ~ 1.5 h. Finally, the temperature was gradually increased to 60 ~ 80°C for 1-5 h, and the reaction was cooled again after completion. After cooling, hydrochloric acid was added in the ice water bath to adjust the PH to 2, and the decolorization was stirred at room temperature. After filtration, sodium hydroxide was added in the ice water bath to adjust the PH to 6-7, and the cooling was stirred for 2 hours. The mass ratio of the third intermediate, sodium hydroxide solution and sodium hypochlorite is 1.0:0.8-1.0:1.0-1.1.
Preparation of Fenebute
1. Prepare the first intermediate
Benzaldehyde and ethyl acetoacetate into ethanol, stir at room temperature under the catalysis of organic alkali reaction with filter cake filtration after 45 ~ 50 h, after the completion of the filter with ethanol elution filter cake, dry cake solids, then ethanol filtrate concentrated to a quarter of the original volume, to cold, concentrate filtering alcohol washing, solid, merging two solid is the first intermediate; The mole ratio of benzaldehyde, ethyl acetoacetate and ethanol is 1:2.5 -3:12-15.
2. Prepare the second intermediate
The first intermediate is added to the mass concentration of 20% sodium hydroxide solution, and the reaction is stirred at 85-90°C for 2-5 hours. After filtration, the filter cake is used for filtration. After filtration, the filter cake is washed, the filtrate is combined and cooled, and the filtrate is cooled by stirring for 3h. Solid second intermediate; The mass ratio of the first intermediate to the sodium hydroxide solution is I: 1.8-2.0;
3. Prepare the third intermediate
The second intermediate was dissolved in pure acetic anhydride solution for reflux 3 ~ 5h. After the reflux, the acetic anhydride was concentrated and dissolved with toluene. After the dissolution, ammonia water was added, and the reaction took place at 60_65°C for 1 ~ 1.5 h. Filtrate, wash and dry the precipitated solid to get the solid third intermediate; The mass ratio of the second intermediate, pure acetic anhydride solution, toluene and ammonia water is 5:1-1.2:0.5-0.8:0.5-0.8;
4. Prepare Finebute
The third intermediate was dissolved in 25% sodium hydroxide solution and cooled to _5°C ~ 10°C. After cooling, sodium hypochlorite was added slowly within 15-20min for 1h reaction, followed by ice bath reaction of 0.5 ~ 1.5 h and water bath reaction of 0.5 ~ 1.5 h. Finally, the temperature was gradually increased to 60 ~ 80°C for 1-5 h, and the reaction was cooled again after completion. After cooling, hydrochloric acid was added in the ice water bath to adjust the PH to 2, and the decolorization was stirred at room temperature. After filtration, sodium hydroxide was added in the ice water bath to adjust the PH to 6-7, and the cooling was stirred for 2 hours. The mass ratio of the third intermediate, sodium hydroxide solution and sodium hypochlorite is 1.0:0.8-1.0:1.0-1.1.
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